By way of re-examining J. S. Mill’s thoughts on liberal imperialismthat consist of a theory of non-intervention and a theory of state-building,this article is meant to offer a re-interpretation of his political theory, so as,on the one hand, to challenge Michael Walzer’s communitarian readingand, on the other, to meet some recent criticisms made from those whointerpret Mill either as a an originator of democratic peace or as a liberalimperialist.It reads Mill’s autobiography in the light of the doctrine of“experiments in living” highlighted by Isaiah Berlin and the ensuingnew wave of attempts that try to reconcile Mill’s utilitarianism withliberalism. Furthermore, the resulting interpretation presents Mill’s liberalimperialism as a theory which is of a piece with his defence of individualliberty and support for utilitarianism, with the latter two understood as twologically as well as practically related doctrines linked by his concept of a “progressive being” which in turn is derived from Mill’s reflection on hisown experiments in living.